<h2>DESCRIPTION</h2>

<em>r.buffer.lowmem</em> creates a new raster map showing buffer
(a.k.a. "distance" or "proximity") zones around all cells that contain
non-NULL category values in an existing raster map. The distances of
buffer zones from cells with non-zero category values are user-chosen.

<p>
This is the low-memory alternative to the
classic <em><a href="r.buffer.html">r.buffer</a></em> module. It is
much slower than the classic version, but will run on massive raster
maps without using a lot of RAM. If your raster map is larger than
32000x32000 cells on a system with 1 GB of RAM, or larger than
90000x90000 cells on a system with 8 GB of RAM, consider using this
module.

<p>
For more info see manual of <em><a href="r.buffer.html">r.buffer</a></em>.

<h2>EXAMPLE</h2>

In the following example, the buffer zones would be (in the default units
of meters): 0-100, 101-200, 201-300, 301-400 and 401-500.

<div class="code"><pre>
r.buffer.lowmem input=roads output=roads.buf distances=100,200,300,400,500
</pre></div>

Result:

<div class="code"><pre>
r.category input=roads.buf

      1       distances calculated from these locations
      2       0-100 meters
      3       100-200 meters
      4       200-300 meters
      5       300-400 meters
      6       400-500 meters
</pre></div>

<h2>SEE ALSO</h2>

<em>
<a href="g.region.html">g.region</a>,
<a href="r.buffer.html">r.buffer</a>,
<a href="r.cost.html">r.cost</a>,
<a href="r.grow.distance.html">r.grow.distance</a>,
<a href="r.mapcalc.html">r.mapcalc</a>,
<a href="r.reclass.html">r.reclass</a>,
<a href="v.buffer.html">v.buffer</a>
</em>

<h2>AUTHORS</h2>

Michael Shapiro, U.S. Army Construction Engineering 
Research Laboratory
<br>
James Westervelt, U.S. Army Construction Engineering 
Research Laboratory
<br>
Low-memory Python version by Glynn Clements

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